Stabilized methylchloroform compositions

ABSTRACT

STABILIZED METHYLCHLOROFORM COMPOSITIONS ARE PROVIDED BY THE INCORPORATION THEREIN A MINOR CONCENTRATION OF ONE OR MORE VARIOUS ADDITIVES. NITRILES SUCH AS ACETONITRILE ARE NOTED.

United States Patent Ofice 3,564,063 STABILIZED METHYLCHLOROFORMCOMPOSITIONS Charles L. Cormany, Wadsworth, William R. Dial, Akron, andBlaine 0. Pray, Wadsworth, Ohio, assignors to PPG Industries, Inc.,Pittsburgh, Pa., a corporation of Pennsylvania No Drawing. Originalapplication Feb. 3, 1958, Ser. No. 712,693. Divided and this applicationMay 7, 1969, Ser. No. 82,707 The portion of the term of the patentsubsequent to June 2, 1987, has been disclaimed Int. Cl. C07c 17/40,17/42 US. Cl. 260-6525 1 Claim ABSTRACT OF THE DISCLOSURE Stabilizedmethylchlorotorm compositions are provided by the incorporation thereina minor concentration of one or more various additives. Nitriles such asacetonitrile are noted.

RELATED APPLICATION This application is a divisional of co-pendingapplication Ser. No. 712,693 filed Feb. 3, 1958 now Pat. No. 3,515,925.

This invention relates to the stabilization of methylchloroform. Moreparticularly, it deals with the protection of methylchloroform againstdecomposition, reduction of its corrosive action, particularly onmetals, and avoidance of other such instability as is evidenced bymethylchloroform during its normal use.

Methylchloroform, 1,1,1-trichloroethane, is a normally liquidchlorinated hydrocarbon valuably employed as an industrial solvent forany of a wide number of applications. One principal use is as a liquidphase degreasing solvent. Metal articles are immersed in liquidmethylchloroform to remove from the article greases, oils and the likein liquid degreasing. In such usage, methylchloroform evidences a strongtendency to decompose. This decomposition is particularly alarming wi-thlight metals such as aluminum, magnesium and their alloys, especiallywhen traces of Water are present. Within all too short a period,decomposition occurs to such an extent that the methylchloroform losesits practical value and also may damage the metals being treated.

Another important use for methylchloroform is as a vapor pressuredepressant in conjunction with areosol. It serves to reduce the pressurein a closed metal container of the aerosol. Because of its peculiarnature, methylchloroform corrodes the metal container, especially ifwater is present. It also decomposes under these conditions of use.

A still further use to which methylchloroform may be put is as a vaporphase degreasing solvent. In this type of degreasing, vaporizedmethylchlorotorm contacts metallic articles from which oils, greases andthe like are removed. Serious decomposition or other degradation ofmethylchloroform occurs during vapor degreasing which, unlesscounteracted or otherwise minimized, is a significant deterrent to itsusefulness as an eflective vapor degreasing solvent.

These and other problems of stability, including decomposition,corrosiveness and the like, especially those which arise in connectionwith the industrial uses of methylchloroform are quite serious. Unlessthey are overcome or substantially minimized, methylchloroform cannot beused with complete effectiveness. and efficiency.

Methylchloroform presents its own unique difliculties regardingstabilization. Thus, experiences in the stabiliza- Patented Feb. 16,1971 tion of other halogenated hydrocarbons are not applicable.

It has now been discovered, in accordance with this invention, thatmethylchloroform may be stabilized so as to reduce or eliminate, amongother things, its corrosiveness, tendency to decompose and the like byincorporating therein a minor concentration, up to about 10 percent byweight thereof, preferably from 0.05 to 5 weight percent, of certaincompounds. By providing a methylchloroform composition containing astabilizing concentration of one or more such compounds, itscorrosiveness, tendency to decompose and other disadvantages, especiallythose observed during its use may be obviated or minimized to the extentthat they are no longer serious. Methylchloroform stabilized in thismanner is of enhanced value.

Compounds which may be used to provide in methylchloroform one or moreof the desired stabilizing effects are:

Ketones, including aliphatic, cycloaliphatic and aralkyl ketones, suchas:

acetone methyl ethyl ketone methyl n-propyl ketone methyl isopropylketone diethyl ketone hexanone-Z heXanone-3 methyl t-butyl ketone methylisobutyl ketone di-n-propyl ketone diisopropyl ketone diisobutyl ketoneacetyl acetone mesityl oxide phorone cyclohexanone acetophenone Ketols(ketone alcohols) such as:

acetol 4-hydroxy Z-butanone 5 -hydroxy 3-pentanone Sulfoxides such as:

dimethyl sulfoxide diethyl sulfoxide methyl ethyl sulfoxide di-n-propylsulfoxide di-n-butyl sulfoxide diisopropyl sulfoxide Nitriles such as:

Imines such as:

alkyleneimines, e.g., ethyleneimine, propyleneimine hydroxypropyleneimine butadiene oxideimine 0 N-alkyl substitutedalkyleneimines, including N-ethyl- Oxaziranes, thioaziranes,oxaphosphiranes and thiophosphiranes of the formula wherein Y isnitrogen or phosphorous and Z is oxygen or sulfur and R is a lower alkylgroup of 1 to 4 carbon atoms, e.g., methyl, ethyl, propyl, isopropyl,n-butyl or isobutyl group.

Trialkylsilylethers, including trimethylsilylethers of the typetrimethylsilylisopropylether, trimethyl butylether,triethylisopropylether.

Dialkyl sulphides, such as dimethyl sulphide, diethyl sulphide, methylether sulphide, dipropyl sulphide, di-isopropyl sulphide.

Dialkyl sulphites, e.g., dimethyl sulphite, diethyl sulphite, ethylmethyl sulphite, dipropyl sulphite.

Tetraalkyl leads, such as tetraethyl leads, tetramethyl lead andcorresponding polyalkyl tin or like metal compounds such as tetraethyltin, tetramethyl tin, triethyl tin, diethyl tin.

Other useful compounds are: morpholines, such as morpholine andN-alkylmorpholines,

including N-methylmorpholine nitroalkanes, including nitromethane,nitroethane, nitropropane hydrazine hydroxylamiue organic derivatives ofhydroxylamine, such as wherein R R and R are lower alkyl groups of 1 to4 carbon atoms and R and/ or R may also be hydrogen.

organic derivatives of hydrazine, such as phenylhydrazine,hydroxyethylhydrazine, and those having the chemical structure whereinR, R and R are alkyl groups of 1 to 4 carbon atoms and/or wherein R andR may be hydrogen. dioxolane methylethanolamine and like hydroxyamines,including ethylethanolamine It has further been found particularly thatcombinations of one or more of the above compounds with alcohols,especially monohydric aliphatic alcohols, or organic epoxides (oxiranecompounds, those compounds having an oxygen atom linked to two adjacentlinked carbon atoms, e.g., the group are especially useful in thestabilization of methylchloroform. These alcohols and epoxides are inthemselves capable of imparting stabilizing properties.

Among the alcohols are: methanol ethanol isopropanol n-butanol propanolOrganic epoxides include:

ethylene oxide propylene oxide glycidol butylene oxides (each isomer oran isomeric mixture) epichlorohydrin styrene oxide cyclohexene oxideCombinations of dimethyl sulfoxide or like dialkyl sulfoxide with anepoxide such as glycidol and acetol with a lower aliphatic monohydricalcohol or epoxide such as glycidol are especially effective.

When more than one compound is employed for stabilizing purposes, thetotal concentration of these oompounds should be between 0.05 and 10percent, preferably less than 6 percent, by weight of themethylchloroform. The concentration of the individual component in suchstabilizing may be varied. Usually, the respective constituents are inequal weight concentrations. However, this is not essential and oneconstituent may be used in greater concentration.

The following examples illustrate the stabilizing effect of variouscompounds:

EXAMPLE I The test procedure used to evaluate the stabilizing effect ofvarious compounds in methylchloroform involved placing 50 cubiccentimeters of methylchloroform in a 250 cubic centimeter glass flaskand thereafter refluxing, under atmospheric conditions, themethylchloroform under total reflux. As indicated in Table I,hereinafter, small strips of aluminum /2 inch by /2 inch polishedaluminum) were included in the bottom of the flask and, hence, immersedin the boiling methylchloroform. The stabilizing compound was includedin the methylchloroform charged to the flask in the concentrationindicated in Table I. Refluxing was continued until the stabilizedeffect of the compound or mixture of compounds was no longer observed asindicated either by the formation of tars, evolution of hydrogenchloride and appearance of precipitates.

Without the use of a stabilizer, methylchloroform in the presence ofaluminum strips turned black (indicating undesirable decomposition)after about 5 minutes of refluxing.

The following table lists various tested compounds and their observedstabilizing effect:

TABLE 1 Total reflux time before Concentration, decompopercent by sitiouStabilizer name weight (hours) None 0. 1 Aeetol 1. 0 109B-methylamlnopropionitrile.. 1. 0 134 Malononitrile 1. 0 16. 3 1. 093 1. 0 52. 6 1.0 134 1. 0 1 i so. 1

0 0. 01 80. 0 60. O hi l iii 3: 0 1 10 3. 0 2-2 32 gig 104 5:?) g 43 isi? a: 0 184 3-8 184 31 0 144 i. 0 52 0 0.01 i Morpholiue 5. 0 20 1Testing stopped; no decomposition occurred during this time interval.

5 EXAMPLE II A further test procedure involved filling a small glassvial with about 20 cubic centimeters of methylchloroform (includingstabilizer as indicated below) and one cubic centimeter of water andstoppering the vial after placing in the vial a mild steel test strip /2inch by 2 inches by inch) such that it was both immersed in the liquidand exposed to the atmosphere of the vial. This vial was then set asideand corrosion of the steel 6 the atmosphere of the vial was observed asa function of time.

The following Table II lists results of such tests with variouscompounds.

While the invention has been described with reference to specificdetails of certain embodiments, it is not intended that it be construedas limited to such details except insofar as they are recited in theappended claim.

We claim:

1. Methylchloroform containing from 0.05 to 5 persubmerged in theliquid, at the liquid interface and in 10 cent acetonitrile by weight.

TABLE II Concentration, Appearance of steel strip after 192 hourspercent by Stabilizer name weight Liquid phase Vapor phase InterfaceNone Slight rust Slight rust Slight rust. Gylcidol 1.0 Clean CleanClean. Dimethyl Sulfoxide. 1. 0 D GlycidoL- 0. 01 Pyridine 1. 0 Do Buteneo 0t 25 1. 0 Glye 0.01 Methylaminopropionitrile 1. 0 Do.Dimethylaminopropionitrile 1. 0 Do. Thiodipropionitrile 11 0 Do.DimethylaminoethanoL 1. 0 Do. Do. 0. b1 Aeetronitrile 3. 0 DMethylethanolamine 1. 0 i Dimethylaminoacetoni 1. 0 Do.Methylrnorpholine 1.0 Do. ii-lifilit ijjijjjiiii 0. 2)? Flight rustReferences Cited UNITED STATES PATENTS 1,948,045 2/1934 Parkhurst260652.5UX 2,043,260 6/1936 Missbach 260652.5 2,947,792 8/1960 Skeeters260-652.5 3,445,532 5/1969 Richtzenhain et al. 260652.5

FOREIGN PATENTS 765,522 1/1957 Great Britain 260652.5

HOWARD T. MARS, Primary Examiner 2 3 UNITED STATES PATENT OFFICECERTIFICATE OF CORRECTION Patent No. 3,564,063 Dated Februarv 16, 1971Inventor(s) Charles L. Cormany, William R. Dial and Elaine O. P:

It is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

[- On the Letters Patent the Serial No. is indicated as "82,707" insteadof --822,707--.

Signed and sealed this 7th day of September 1971.

(SEAL) Attest:

EDJARD M.FLETCHER,JR. ROBERT GOTTSCHALK office! Acting Commissioner ofPatents

